Nuts, Bolts, and Screws at


What are the different types of nuts and bolts carried by G.L. Huyett?

Coupling Nuts

Coupling Nuts

Coupling nuts, also known as extension nuts, are elongated internally threaded nuts used to join two male threads. Coupling nuts are often used for joining threaded rods or hanger bolts in a variety of applications that require extending threaded rod or attaching like items. G.L. Huyett's online selection offers coupling nuts from a range of lengths and thread sizes. Find coupling nuts for your next project by browsing our catalog.

  • Available in stainless steel, carbon steel, and brass
  • Also available in plain and zinc clear finishes
  • Common hex design allows for simple tightening and loosening with a standard wrench

Hex Nuts

Hex Nuts

Hex nuts are a six‑sided nut and are the most commonly shaped nut today. They are used with anchor shackles, bolts, screws, and other externally threaded components. Hex nuts, in conjunction with these other fasteners, are used to connect both metal and wood components to prevent tension and movement.

  • Available in carbon steel, stainless steel, and nylon
  • Offered in plain or zinc clear finishes
  • Inch and metric sizes available
  • Works in tandem with various locking mechanisms for applications subject to vibration

Jam Nuts

Jam Nuts

Jam nuts are a low‑profile hex nut used as a locknut to prevent vibration from loosening a bolted joint. Before nuts were developed with "self‑locking" capabilities, two jam nuts would be tightened against each other so that nuts wouldn't loosen over time. The first nut is held with a wrench while the second nut is tightened or "jammed" against the first to lock both nuts in place.

  • Available with both left‑handed and right‑handed threads
  • Low‑profile design makes this nut ideal for low clearance applications
  • Overall height is similar to a standard hex nut when jam nuts are doubled
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Lock Nuts

Lock Nuts

Lock nuts resist loosening due to vibration, which makes them an essential piece of hardware for a multitude of applications. Unlike free spinning nuts, lock nuts make use of a deforming elastic or metal material to stay in position against torque and shock. Other common names for lock nuts include locking nuts, prevailing torque nuts, stiff nuts, locknuts, or elastic stop nuts. Many lock nuts use a nylon insert for the uppermost thread which creates the friction necessary to create a lock against the properly sized mating component. Although lock nuts with elastic inserts are often reusable, the amount of torque generated can lessen with use. Upgrade your lock nuts from among the high‑quality selection available from G.L. Huyett.

  • Resists loosening caused by vibration
  • Lock nuts are often reusable
  • Available in plain, zinc clear, zinc black, and black oxide
  • Offered in metric and imperial sizes



Bolts are a common fastener often used in concert with a hex nut to join two or more work pieces together. G.L. Huyett offers a variety of bolt styles to fit your unique needs. Standard hex bolts and U‑bolts are in stock and ready to ship with J‑bolts and L‑bolts available upon request. If you don't see what you're looking for, contact us to speak with our friendly, knowledgeable sales team!

  • J‑bolts and L‑bolts provide great anchors in concrete or masonry
  • U‑bolts are a great solution for attaching or suspending pipe and conduit
  • Most varieties are offered in corrosion resistant zinc plating
  • Nut and bolt assortments also available

Nut & Bolt Assortments

Nut & Bolt Assortments

G.L. Huyett offers a broad range of metric and imperial nut and bolt assortments available in stainless steel or zinc plated carbon steel. Choose from lock nuts, wing nuts, carriage bolts, hex bolts, as well as nut and bolt assortments. Pre‑packaged assortments are in stock and ready to ship, or give us a call to create a custom assortment complete with your branding.

  • Customizable to fit your needs
  • Convenient plastic case with dividers to keep parts organized
  • Provides quick, easy access to frequently used parts
  • Attached visual product layout helps quickly identify nut and bolt types and sizes
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Cap Screws

Cap Screws

Cap screws, or capscrews, are an externally threaded fastener manufactured to close tolerances. Common head types encompass socket and hex head screws that can be tightened or loosened using an allen style wrench or end wrench. Threads on hex socket cap screws typically run the full length of the screw shank and can be matched to a threaded hole or coupled with a hex nut. Cap screws are precision manufactured and often used in applications that require high tensile strength.

  • Available in alloy and stainless steel material
  • Offered in plain or black oxide finish
  • Knurled head provides easy handling during assembly and disassembly

Set Screws

Set Screws

A set screw is a hardened, threaded fastener designed to hold adjustable components on a shaft. Some set screw variations possess a hex head, while headless, sometimes called grub screws, are characterized by a hex or slot recess to allow for tightening and loosening. Set screws are an effective way to hold pulleys, gears, and other components on shaft while still allowing adjustment of the retained part.

  • Allows for simple adjustment of a part
  • Offered in hardened alloy, carbon, and stainless steels
  • Available in black oxide finish for additional corrosion resistance

Standard Screws

Standard Screws

G.L. Huyett offers a wide range of screws at great prices. Our metric and imperial screws are available in carbon and stainless steel as well as nylon and plastic materials. Use them to assembly nearly anything from common use applications to unique prototype assemblies. If you don't see what you are looking for or you're not sure which fastener is best for your application, contact us to speak with our knowledgeable, friendly sales team.

  • Common types include machine screws, hex cap screws, and tap screws
  • Carbon steel fasteners available in phosphate and zinc finishes for added corrosion resistance
  • Nylon screws feature great insulation properties making them ideal for a variety of applications



What is a coupling nut?

A coupling nut, also called an extension nut, is designed to join two male threads. Its hexagonal shape allows the nut to be tightened using a common open end wrench.

How to measure a coupling nut?

A coupling nut can be measured by its internal threads (X) as well as its measurement across its hexagonal flats (B) and profile height (A).

Coupling Nut Measurement

How to use a coupling nut:

A coupling nut is often used to connect two ends of threaded rod.

  1. Thread one end of the desired rod roughly halfway into the coupling nut.
  2. Take the end of the second rod and thread it into the remaining open end of the nut and thread until snug.
  3. Use a properly sized wrench to finish tightening the nut to the desired torque.
Coupling Nut Use

What is a hex nut?

Hex nuts are a common, internally threaded fastening solution used in conjunction with bolts or screws. As the name implies, hex nuts possess a hexagonal shape whose faces serve as a wrenching surface. They are available in a variety of metric and imperial sizes and crafted in carbon and stainless steel as well as nylon. Hex nuts are used across nearly every industry from household appliances to aerospace.

Hex Nut Use


What is a jam nut?

Jam nuts are a hexagonal nut featuring a much thinner profile as compared to a standard hex nut. They are often used in pairs to prevent unwanted loosening of a bolted assembly. Jam nuts are often used in applications where tight clearances are present.

How to use a jam nut as a lock nut:

  1. Thread one jam nut onto the shaft of a bolt or screw.
  2. Tighten the jam nut down against the surface of the assembled component, torqueing it to the desired specifications.
  3. Thread a second jam nut onto the shaft of the bolt or screw.
  4. Hold the first jam nut securely with a wrench while tightening the second jam nut securely against it.
Proper Jam Nut Usage

How does a lock nut work?

Lock nuts, sometimes called prevailing torque nuts, are designed to prevent the loosening of bolted assemblies caused by vibration. When they are tightened down onto a threaded fastener, lock nuts apply added frictional force against the threads of the mating fastener. Different varieties of lock nuts provide added friction through a multitude of methods, ranging from nylon inserts to irregular threads.

Lock Nut


What is the difference between a bolt and a screw?

The difference between bolts and screws is simple. While both are cylindrical, externally threaded fasteners, each possess different functions making them unique. Bolts are crafted with various head types and are often used in through holes applications. Tightening occurs when the bolt is mated with an internally threaded nut.

Screws are also crafted with a variety of head types. However, they are typically used in blind holes of assembled parts. Screws can use preformed threads of a blind hole or form threads of their own depending on mating material and screw type. Due to their basic design, some screws can be used with internally threaded nuts.

What is a cap screw?

A cap screw, or capscrew, is an externally threaded fastener manufactured to close tolerances and designed for applications requiring fasteners with high tensile strength. They are often used in pre‑threaded, blind holes and tightened by rotating the head of the screw with a socket or wrench. Cap screws can be found anywhere from retaining exhaust manifolds to household furniture. Cap screws are typically made from alloy and stainless steel with some specialty varieties made from brass, bronze, or aluminum.

Cap Screw Use

How are cap screws measured?

Cap screws are measured from just under the head, where it seats against a mating surface, to the opposite end of the shank (L). For cap screws with a countersunk head, length is measured at the beginning of the taper to the end of the shank (Y).

Cap Screw Measurement

Are cap screws fully threaded?

The most common cap screw types feature a fully threaded shank. However, some specialty variations possess partially threaded shanks.

What is a set screw?

A set screw is a hardened, threaded fastener designed to hold adjustable components on a shaft. Some set screw variations possess a hex head, while headless (sometimes called grub screws) are characterized by a hex or slot recess to allow for tightening and loosening. Set screws are often used to hold pulleys, gears, and other components on a shaft. They hold components in place by employing compressive forces onto the mating shaft, reducing unwanted movement of attached assemblies.

How does a set screw work?

Set screws use compressive forces to hold assembled components in place. They are threaded into a tapped hole, such as on shaft collars, and tightened until the end of the screw presses against the mating shaft. When selecting the appropriate set screw, take material hardness into consideration. To be effective, the set screw should be a harder material than the shaft it is engaging. For additional holding power, some set screws are designed with a point that swages shaft material when the screw is tightened.

Set Screw Application

How are set screws measured?

Set screws are measured by their length and thread size. The screw's length (L) is measured end to end while threads (Y) are measured by shank diameter and thread pitch.

Set Screw Measurement